The piston stop is universally applicable, yes, but in the case of Fords with offset cranks some version of splitting (stops or measurement) is necessary to really pin down TDC. Just an indicator can do the job adequately on a straight up engine, but produces a foggy area of about 3 degrees over an offset crank.
Of course here we are looking for the source of a fairly large problem, looking at the location of a hole that could be analyzed with eyeball TDC.
But...another issue here is that the engine sports a timing indicator gadget. Doing TDC accurately would allow this thing to be checked, and I would bet it is pretty shaky there...